OZ Minerals has become the latest major mining company to undergo a leadership transition, with CEO Terry Burgess departing by Q4 amid 2013 losses reported at $265 million.

Last year, OZ focused on its flagship copper-gold operation at Prominent Hill, along with pre-feasibility studies at Carrapateena and potential acquisitions, said Burgess.

Despite losses, moreover, 2013 “was a year of investment,” he added, with waste movement peaking at Prominent Hill’s Malu open pit and as “a successful first year of production from Ankata Underground and work toward development of a third mine, Malu Underground.”

With shares tumbling more than 50% since last year, the replacement of Burgess, who has led the Australian miner since Q3 2009, though, wasn’t unexpected. “I think it is appropriate to embark on a considered leadership change,” he said, according to a statement quoted by The Sydney Morning Herald.

In Q4, OZ missed guidance after mining in areas that had not been fully drilled out, according to analysts. Charges also emerged that company officials eroded more than $1 billion earmarked for acquisitions, reported The Herald; cash standing was $364 million by the end of 2013.

Burgess had long promised 2013 would be a difficult year for OZ as it chewed through low grade materials. Indeed, his forecast prevailed with last year’s results $406 million worse than the profit recorded in 2012.

In addition to lower grades, demand and impairments linked to property and plant and equipment at OZ’s flagship Prominent Hill mine also hurt the Melbourne-headquartered company.

In all, OZ produced 73,362 copper tons, and 128,045 gold oz in 2013. Guidance for 2014 is expected to surpass these figures, said officials, via significantly lower costs at up to 80,000 copper tons and 140,000 gold oz.